XJR, do you still have access to the original ad for the studentship? There usually a name in those ads. In my case, I first found the supervisors and applied to funding after that. So it is completely a different situation than yours. But all I can say is it is your right to know what the supervisory arrangements are. Try to do some background research about the position, but if you can't find anything it is alright to ask at the interview.